Show boss Simon Cowell, 53, is desperate to get her back but Nicole is still undecided about rejoining X Factor, which holds live shows in the autumn.

Stunning Nicole

A source close to the couple revealed: “Nicole and Lewis have the utmost respect for one another’s careers and will go out of their way to be there on big occasions.

“But with most of the races in October, November and December outside Europe, they are genuinely going to struggle to meet up.

“Lewis has said to Nicole this is going to be an awful ­situation and ­perhaps she shouldn’t do it.

“If he thought she had her heart set on returning he wouldn’t say this but he knows she isn’t desperate to go back and thinks she would be happier if they were together.

“Nicole is also worried that she won’t see much of Lewis so it is a big factor that will deeply affect her decision.”

Last month Nicole told Cowell she would only return if they doubled her £750,000 deal. The producers duly upped her fee but Nicole, who also had a stint on US X Factor, still has ­concerns about a potential clash with her ­music commitments.

She is due to release a ­single and album in November, meaning she will need to ­promote it around the world while appearing on X Factor.

A source close to Nicole said: “She is a global star and has to ­promote her work ­everywhere so she’ll be forced to miss a lot of X Factor.

“To some judges this wouldn’t be a problem but Nicole isn’t like that, she gives her all to her contestants.”

A source close to Lewis said: “Lewis is extremely supportive of Nicole’s career and is thinks if she does ­decide to do the X Factor then at least she has something to occupy her while he is away racing.”

Cowell is due to re-sign Sharon Osbourne, 60, in place of Tulisa Contostavlos, 24.

Louis Walsh, 60, will return but Take That star Gary Barlow, 41, is yet to decide whether he will be back for a third stint as head judge.